Liquid distribution apparatus

ABSTRACT

A manifold has a first inlet means for connection with a liquid to be distributed, this inlet means being in communication with a plurality of spaced outlet holes through which the liquid is dispensed. A second inlet means is adapted to be connected with a cleaning solution, and valve means is provided for selectively connecting the second outlet means with the outlet holes. A plurality of individual plungers are reciprocably mounted within the manifold, each of the plungers having a sliding fit with one of the outlet holes for closing the outlet holes and for forcing out any particles which tend to clog the outlet holes.

United States Patent 1 1 3,557,820

[72] Inventors Dale E. Jackson [56] References Cit d g' 'g"1 V K nUNlTED STATES PATENTS [21 1 A I No a 2,296,079 9/1942 Anderson 239/118 73,059,856 10 1962 Pagendarmm. 239 117 [-2] F1led Aug. 28, 1968 3,134,6925/1964 Arneson 222/ 1X Patented Jan. 26, 1971 3 3411221 91967 B [73]Assignee Butler Manufacturing Company, x ames 239/1 12X Kansas City,Mo., Primary Exa' inerRobert G. Nilson a corporation of MissouriAttorney-S oemaker and Mattare ABSTRACT: A manifold has a first inletmeans for connection with a liquid to be distributed, this inlet meansbeing in communication with a plurality of spaced outlet holes through[54] :5 9? APPARATUS which the liquid is dispensed. A second inlet meansis adapted alms rawmg to be connected with a cleaning solution, andvalve means is [52] US. Cl 137/244, provided for selectively connectingthe second outlet means 137/239, 222/149, 239/1 12, 239/1 17 with theoutlet holes. A plurality of individual plungers are [51] Int. Cl B05b15/02 reciprocably mounted within the manifold, each of the plun- Fieldof Search 239/1 12, gers having a sliding fit with one of the outletholes for closing the outlet holes and for forcing out any particleswhich tend to clog the outlet holes.

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PATENTEDJAN26|91| SHEET 1 OF 4 INVENTORS DALE E.JACKSON 8| CARL C.PERKINSQJR.

ATTORNI'IYS PATENTEU JAN 2 6 I9?! SHEET 3 0F 4 m Q O u m ms A E W L KKMg a JP \W EC. J

l..- Lmm QM MGM m ATTORNEYS LIQUID DISTRIBUTION APPARATUS The presentinvention relates to liquid distribution apparatus for distributing aliquid mixture across a substrate along a line generally perpendicularto the direction of relative movement of the substrate and theapparatus. The present invention is directed to the distribution ofsubstrates of precursors of thermosetting elastomers and plastics toform foams, reinforced articles, castings, adhesives and coatings. Thesubstrate may be flexible such as belts, paper or foil and the like. Thesubstrate may also be rigid such as a sheet of metal. lfthe manifoldoperates between two such rigid sheets, a sandwich panel may be formed.Examples of thermosetting compositions which may be distributed with thepresent invention are polyurethanes, unsaturated polyesters, acrylics,epoxies, phenolics, ureas and melamines. The apparatus may also be usedfor distributing inorganic cements whose setting action is chemical,e.g., silicates, aluminates, and magnesium ox ychlorides or oxysulfates.The present invention may also be employed for spreading molten asphaltand coal tar.

In the prior art. lateral distribution of liquids across the width of anelongated substrate has been generally accomplished by manifoldscomprising pipes or tubes of constant diameter. The main passageway ofsuch pipes or tubes usually terminates near the outermost orifice formedin the pipe or tube through which the liquid is dispensed. The liquidsemployed with this type of construction are generally of two types,firstly, a nonreactive material which is heated in order to reduce itsviscosity for adequate flow, and secondly, a chemically reactivematerial which gels, hardens or expands within a preset time after it ismixed or catalyzed. When utiliz' ing such prior art constructions, anumber of problems have arisen. Partially reacted resinous materialstend to collect in dead areas of the tubes or conduits and dislodge inpieces to clog the outlet holes which are usually simply holes drilledthrough the tube or pipe. Accordingly, it is necessary to completelyremove the manifold from the machine and then disassemble the manifoldfor soaking or mechanical abrading to clean the manifold. If one or moreof the outlet holes of such a manifold should be partially or completelyblocked or plugged, the manifold must be replaced or removed andcleaned. In any event. it is impossible to carry out a continuousprocess with such prior art arrangements.

If it is desired to flush out a manifold as employed in knownconstructions with a solvent and the like, the manifold or the substratemust be moved in order to avoid contamination of the final product.

Prior art constructions employing pipes or tubes of constant borerequire outlet holes of different diameter in order to obtain controlleddeposition of the liquid. Additionally, with this type of arrangementthe flow rate decreases as the distance from the inlet increases therebyenhancing the possibility of partially reacted material collecting inthe main passageway of the apparatus.

An additional disadvantage of known arrangements is the fact thatflushing must be carried out parallel to the flow of the dispensedliquid, which of course is less efficient than reverse flushing.

SUMMARY OF THE INVENTION In the present invention, a plurality ofplungers are reciprocably mounted within a manifold means, each of theseplungers having a sliding fit with one of the outlet holes of themanifold means. Accordingly, if one or more of the outlet holes shouldbecome partially or completely plugged or blocked, the plunger means canbe slid into the holes to dislodge any undesired particles. This can bedone without removing the manifold from the apparatus, and furthermorethe procedure can be carried out very quickly so that substantially nointerruption of a continuously operating process is necessary.

The manifold means of the present invention also includes an inlet whichis adapted to be connected with a cleaning solution. Valve means isincorporated in one or more of the plungers so that the cleaningsolution can be selectively admitted to the apparatus while the outletholes are closed off. Accordingly, the manifold can be readily reverseflushed when so desired without moving the manifold or the substratewith respect to one another, and the plungers will prevent anypossibility of contamination of the final product.

The inlet means of the present invention which is connected with aliquid to be distributed is in communication with an elongated passagewith which the outlet holes are also in communication. This passage isof decreasing cross-sectional dimension in a direction from the inletmeans toward the ends of the passage whereby a substantially uniformflow velocity of the distributed liquid is maintained throughout thelength of the manifold. The end of the passage terminates at an outlethole so as to eliminate any dead areas in the manifold within whichliquid to be distributed might accumulate.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical section through afirst form ofliquid distribution apparatus of the present inventionillustrating the parts in a first operative position;

FIG. 2 is a view similar to FIG. 1 illustrating the parts in the secondoperative position;

FIG. 3 is a sectional view taken substantially along line 3-3 of FIG. 1looking in the direction of the arrows;

FIG. 4 is a sectional view taken substantially along line 4-4 of FIG. 2looking in the direction of the arrows;

FIG. 5 is a sectional view on an enlarged scale taken substantiallyalong line 5-5 of FIG. 2 looking in the direction of the arrows;

FIG. 6 is an elevation partly broken away of a modified form of theinvention;

FIG. 7 is a sectional view taken substantially along line 7-7 of FIG. 6looking in the direction of the arrows;

FIG. 8 is a sectional view taken substantially along line 8-8 of FIG. 6looking in the direction of the arrows;

FIG. 9 is a sectional view taken substantially along line 9-9 of FIG. 6looking in the direction of the arrows;

FIG. 10 is a top view of still another form of the invention;

FIG. 11 is a top perspective view of the form of the inventionillustrated in FIG. 10;

FIG. 12 is a sectional view on an enlarged scale taken substantiallyalong line 1212 of FIG. 10 looking in the direction of the arrows andillustrating the parts in a firstposition;

FIG. 13 is a view similar to FIG. 12 illustrating the parts in thesecond position;

FIG. 14 is a schematic flow diagram illustrating a first operativeposition of the apparatus in a reverse flushing arrangement;

FIG. 15 is a view similar to FIG. 14 illustrating the apparatus in asecond operative position for reverse flushing;

FIG. 16 is a schematic flow diagram illustrating the apparatus in afirst operative position for parallel flushing of the apparatus; and

FIG. 17 is a view similar to FIG. 16 illustrating a second operativeposition of the apparatus in a parallel flushing arrangement.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawingswherein like reference characters designate corresponding partsthroughout the several views, a first form of the invention isillustrated in FIGS. 1-5 inclusive.

As seen most clearly in FIGS. 1 and 2, a manifold means is indicatedgenerally by reference numeral 20 and includes a first body member 10and a second body member 12, body member 12 being secured to body member10 by a pair of capscrews 14 extending through suitable holes providedin the two body members. A conduit or pipe 21 is adapted to be connectedwith a suitable source of a liquid to be distributed by the apparatus,conduit 21 including a tapered threaded end portion 22 which is threadedwithin an inlet end of an elongated passage 24 formed in body member 10.

A plurality of spaced outlet holes 26 are provided in body member andare in communication with passage 24. It will be noted that thecrosssectional dimension of passage 24 diminishes from the left to'theright as seen in FIGS. 1 and 2 so as to ensure substantially uniformflow velocity of the liquid within passage 24. The right-hand end of thepassage 24 terminates in a right-handmost outlet opening 26.

A pipe or conduit 30 is adapted to be connected with a suitable sourceof a cleaning solution such as a solvent or the like, conduit 30 havinga threaded end portion 32 which is threaded within an inlet end of anelongated passage 34 which is also formed in body member 10.

The right-hand end of passage 34 is enlarged in a downward direction toform the cavity 36 which in turn is in communication through a generallycylindrical passage 38 with the righthand end of the aforementionedpassage 24 formed in the body member.

A plurality of holes 42 extend between passages 24 and 34 and arealigned with each of the outlet holes 26. A plurality of holes 44 arealso formed through the upper portion of body member 10 in alignmentwith the holes 42. A seal 46 is seated within a recess provided in theupper surface of body member 10 in surrounding relationship to each ofthe holes 44.

Body member 12 has a plurality of elongated holes 48 which are alignedwith the aforementioned holes 44, and a plurality of individual plungers50 are slidably positioned within said aforementioned aligned holes forreciprocation in a vertical direction as seen in FIGS. 1 and 2. Theupper ends of the plun gers 50 are secured to an elongated common member54 which is connected with a pair of members 56. These members 56 may beconnected with a power-operating means for suitably controlling thevertical reciprocation of the plungers as desired. While each of theplungers has been illustrated as being interconnected with a commonmember 54, it should be understood that the plungers 50 may also beindividually operated if so desired.

As seen in FIGS. 1 and 2, the right-handmost plunger 50 in cludes anintermediate portion 60 of reduced dimension. The construction of thisrighthandmost plunger 50 is such that it serves as a valve means forcontrolling flow between the two passages 24 and 34 as explainedhereinafter.

FIG. 1 illustrates the apparatus in position for operation wherein aliquid is distributed from the apparatus onto a substrate. In theposition shown in FIG. 1, liquid to be distributed passes into thepassage 24 through the inlet thereof and flows outwardly and downwardlythrough the outlet holes 26.

It should be understood that a substrate disposed beneath thedistribution apparatus as shown in FIGS. 1 and 2 is carried in adirection extending into or out of the paper. The substrate can becarried in the desired direction by a suitable powered conveyor or thelike. In some cases, the manifold may be moved while the substrateremains stationary, or both the manifold and the substrate may move. Themanifold may also be reciprocated perpendicular to the motion of thesubstrate to achieve a better laydown pattern. Any type of conventionalreciprocating device may be employed for this purpose.

If it is desired to force out any particles which may tend to clog orblock the outlet holes 26, the plungers 50 may be reciprocateddownwardly from the position shown in FIG. 1 to that shown in FIG. 2. Ifit is further desired to flush the passage 24, the plungers may remainin the position shown in FIG. 2 and the supply of liquid to bedistributed may be interrupted into passage 24. A supply of solvent-canthen be fed into the passage 34 through pipe 30. It will be noted thatin the position shown in FIGS. 2 and 5, the reduced portion 60 of theright-handmost plunger 50 is disposed within the passage 38 leadingbetween the passages 24 and 34. This reduced portion 30 is ofsubstantially less diameter than the passage 38, and accordingly solventcan pass downwardly through this passage 38 and thence from right toleft through the passage 24 to produce a reverse flush of this passage.

When it is desired to again commence distribution of a liquid throughthe outlet holes, the plungers can be reciprocated vertically back intothe position shown in FIG. 1, whereupon the liquid can be introducedthrough pipe 20 into passage 24 for normal distribution onto asubstrate.

It will be noted that during the flushing operation, the cleaningsubstance or solvent does not pass through the outlet holes, and it canbe carried away to a dump reservoir. After the solvent solution has beenflushed through the apparatus, air may be circulated through theapparatus to remove the excess solvent before further liquid isdispensed through the outlet holes.

Referring now to FIGS. 6 9 inclusive, a modified form of the inventionis illustrated. A manifold means is indicated generally by referencenumeral 70 and includes a pair of mounting brackets 72 and 74 extendingupwardly and offset therefrom. These mounting brackets support stopscrews 76 and 78 respectively for a purpose hereinafter described.Screws 80 are adapted to connect the mounting brackets with a suitablesupport member 82.

A pipe or conduit is adapted to be connected with a liquid to bedispensed or in some cases with a solvent supply as hereinafterdescribed. Conduit 90 includes a tapered threaded end portion 92 whichis threaded within a correspondingly threaded inlet fitting 94 on themanifold.

The manifold has therewithin an elongated passage including a pair ofportions 96 and 98 as seen in FIG. 9 each of which is of decreasingcross-sectional dimension from the central portion of the manifoldtoward opposite ends thereof. A plurality of spaced outlet fittings 100are threaded within suitable holes provided in the bottom of themanifold, each of these fittings having an outlet hole 102 formedtherethrough as seen most clearly in FIGS. 7 and 8.

A pair of inlet fittings 104 are provided at opposite ends of themanifold as seen in FIG. 6. A pair of pipes or conduits 106, one ofwhich is seen in FIGS. 8 and 9, are provided, each of these conduitshaving a tapered threaded end portion 108 threaded within the associatedinlet fitting 104, these conduits being adapted to be connected with asolvent supply or in some cases the liquid to be distributed ashereinafter described.

As seen most clearly in FIG. 8, each of conduits 106 is in communicationwith a chamber 112 which in turn is con nected with the passages 96 or98 previously described through a vertically extending generallycylindrical passage 114. This passage 114 has a seal 116 disposed insurrounding relationship thereto for cooperating with a plungerhereinafter described.

A plurality of bosses 120 are formed on the upper portion of themanifold, each of these bosses having a cap 122 threaded thereon. Eachboss and the associated cap have aligned holes formed therethrough forslidably receiving a plunger 126.

A plurality of such plungers are provided, each plunger having a reducedportion 128 supported at the lower end thereof, this reduced portion 128having a sliding fit within one of the outlet holes 102 previouslydescribed.

A plurality of seals 116 are disposed within suitable recesses formedthroughout the length of the manifold so that each of the cylindricalplungers 126 has sealing engagement with one of the seals 116.

Referring to FIG. 8, the endmost plungers 126 at opposite ends of themanifold are provided with recessed portions 130 whereby these endmostplungers also serve as valve means for controlling the flow of liquidbetween the passages 112 and the passages 96 or 98 disposedtherebeneath.

The upper ends of the plungers 126 are connected with a common elongatedmember by a plurality of separate setscrews 142 whereby each of theplungers is adapted to move in unison with the member 140. This member140 is in turnv operatively connected with a power-operating means 146by a shaft 148. Means 146 may comprise an air cylinder, a hydrauliccylinder, an electric solenoid, or various types of mechanical actuatorsand the like.

The stop screws 78 serve to limit the upward and downward movement ofthe plungers by interengagement with the elongated member 140operatively associated with each of the plungers.

As seen in FIG. 7, the plungers are in their uppermost position whereinthe topmost stop screw 78 engages the upper surface of elongated memberI40. In this position, the plungers are free of the outlet holes, andliquid introduced through the inlet conduit 90 passes outwardly throughthe outlet holes 102. At the same time, communication between the lowerpassages and the conduit means I06 is prevented since the endmostplungers are in their uppermost position closing off the passages I14.

Referring now to FIG. 8, the plungers have been moved into theirlowennost position wherein the undersurface of member 140 engages thelower of the two stop screws 78. In this position, the recessed portion130 of the endmost plungers causes conduits 106 to be in communicationwith the underlying passages 96 and 98.

Referring now to FIG. 14, a schematic flow diagram illustrates anarrangement wherein the structure in FIGS. 6-9 is connected in a systemfor reverse flushing of the apparatus. The conduit means 106 areconnected with a common conduit 150 which is in turn connected through aselectively operable valve 152 with a source of cleaning substance suchas a solvent and the like. The conduit 90 is connected through aselectively operable valve 154 with either a conduit 156 connected witha source of liquid to be distributed, or with a conduit I58 which inturn is connected with a dump reservoir.

In the operative position shown in FIG. 14, valve 152 is closed, andvalve 154 is moved to an operative position so that liquid to bedistributed enters the apparatus through conduit 90 and passes outwardlythrough the aforementioned outlet holes.

When it is desired to reverse flush the structure, the valve 152 ismoved to the open position as shown in FIG. 15, and valve I54 is movedto such a position that conduit 90 is in communication with conduit 158which leads to a dump reservoir or the like. In this operative position,solvent enters the manifold at opposite ends thereof, and the plungersare disposed in their lowermost position so that the solvent will flowdownwardly and thence outwardly through conduits 90 and 158 to the dumpreservoir.

Referring now to FIG. 16, the structure shown in FIGS. 6- 9 isillustrated as being connected in a system for providing parallelflushing of the apparatus.

The conduits 106 are connected with a common conduit 160 which in turnis operatively connected with a dump reservoir. The conduit 90 isconnected through a valve 164 with either a first conduit 166 connectedwith a source of liquid to be distributed, or through a conduit 168 witha source of cleaning substance such as a solvent or the like.

In the operative position of the components as shown in FIG. I6, theplungers are in theiruppermost position, and liquid to be distributedpasses into the apparatus and outwardly through the outlet holesthereof.

When the components are positioned in the relationship shown in FIG. 17,the plungers are in their lowermost position, and solvent enters theapparatus through the conduit 90. The solvent passes through thepassages 96 and 98 of the apparatus and thence upwardly and outwardlythrough the conduits 106 to the conduit 160. It is apparent that in thisarrangement, the direction of motion of the flushing liquid is parallelto the direction of motion of the liquid to be distributed.

Referring now to FIGS. 10-13 inclusive, a further modified form of theinvention is illustrated. This form of the invention is similar to thatshown in FIGS. 6--9 inclusive and includes a manifold 170. As seen inFIG. I], this manifold includes a first pair of inlet conduits I72adapted to be connected with a suitable source of liquid to bedistributed, and a second pair of inlet conduits 174 are connected witha suitable source of a cleaning solution such as a solvent or the like.

As seen most clearly in FIG. It), the conduits I74 are disposed incommunication with upper passages I76 which are of decreasingcross-sectional dimension in a direction from the ends of the manifoldtoward the central portion thereof. Similar lower passages 178 aredisposed beneath passages 176 and are in communication with the conduits172.

A plurality of bosses I are provided on the upper part of the manifold,and caps 182 are threaded thereon. A plurality of plungers 184 similarto those previously described are disposed for vertical reciprocationwithin suitable aligned holes provided in the various members. The lowerends 186 of the plungers 184 are of reduced dimension, and rubber O-ringseals 188 are supported within recesses in the manifold for engaging andproviding a seal with the associated plungers. A recess portion I isfonned in the central plunger as seen most clearly in FIGS. 12 and 13.

A plurality of outlet fittings 194 are secured along the length of thebottom wall of the manifold and have outlet holes 196 formedtherethrough for distributing liquid therefrom.

The mode of operation of this form of the invention is similar to thatpreviously described, it being understood that when the plungers are intheir uppermost position as shown in FIG. I2, liquid is distributedthrough the outlet holes 196, and on the other hand, when the plungersare in their lowermost position as shown in FIG. 13, communication isprovided between the upper passages 176 and the lower passages I78whereby a cleaning solution such as a solvent may be circulated throughthe manifold for flushing out the structure. It is, of course, apparentthat the lower ends of the plungers are adapted to push out anyparticles which tend to clog or obstruct the outlet holes.

While the diminishing cross section of passage 24 will generally insuresubstantially uniform flow of liquid within the passage, in certaininstances the size of the outlet holes 26 and plungers 50 may also bevaried in order to obtain uniform flow.

As this invention may be embodied in several forms without departingfrom the spirit or essential characteristics thereof, the presentembodiment is therefore illustrative and not restrictive, and since thescope of the invention is defined by the appended claims, all changesthat fall within the metes and bounds of the claims or that form theirfunctional as well as conjointly cooperative equivalents are thereforeintended to be embraced by those claims.

We claim:

1. Liquid distribution apparatus comprising manifold means, saidmanifold means having first inlet means for connection with a liquid tobe distributed, said manifold means having a plurality of spaced outletholes formed therein and in communication with said first inlet meansfor distributing liquid, said manifold means having second inlet meansfor connection to a cleaning solution, and plunger means movably mountedwith respect to said manifold means for movement into and out of saidoutlet holes for closing the holes and forcing out any particles tendingto clog the holes, and means for automatically connecting said secondinlet means with said outlet holes when said plunger means moves intosaid outlet holes and closes said outlet holes.

2. Apparatus as defined in claim 1 wherein said plunger means comprisesa plurality of separate plungers each of which has a sliding fit withone of said outlet holes.

3. Apparatus as defined in claim 1 wherein said means for automaticallyconnecting said second inlet means with outlet holes comprises valvemeans.

4. Apparatus as defined in claim 1 wherein said manifold means has anelongated passage formed therein in communication with said first inletmeans, said outlet hoies opening into said passage said passage being ofdecreasing cross-sectional dimension from said first inlet means towardthe opposite end of said passage.

5. Apparatus as defined in claim 4 wherein said first inlet means isdisposed adjacent the midportion of said manifold means and saidelongated passage is of decreasing cross-sectional dimension in oppositedirections from the center of said manifold means.

6. Apparatus as defined in claim 4 wherein said first inlet means isdisposed adjacent one end of said manifold means, said elongated passagedecreasing in cross-sectional dimension toward the central portion ofsaid manifold means.

7. Apparatus as defined in claim 1 wherein said plunger 'means comprisesa plurality of separate plungers each of which has a sliding fit withone of said outlet holes, and seal means disposed in surroundingrelationship to each of said plungers to provide a liquid-tight sealtherewith.

8. Apparatus as defined in claim 7 including means for selectivelyreciprocating said plungers.

9. Apparatus as defined in claim 1 wherein said plunger means comprisesa plurality of separate plungers each of which has a sliding fit withone of said outlet holes, the end portion of each of said plungers whichis adapted to slide within one of said outlet holes being of reduceddimension as compared to the remainder ofthc associated plunger.

10. Liquid distribution apparatus comprising manifold means, saidmanifold means having first-inlet means for connection with a liquid tobe distributed, said manifold means having a plurality of spaced outletholes formed therein and in communication with said first inlet meansfor distributing liquid, said manifold means having second inlet meansfor connection to a cleaning solution, plunger means movably mountedwith respect to said manifold means for movement into and out of saidoutlet holes for closing the holes and forcing out any particles tendingto clog the holes, and valve means for selectively connecting saidsecond inlet means with said outlet holes, said plunger means comprisinga plurality of separate plungers each of which has a sliding fit withone of said outlet holes, said valve means being incorporated in atleast one of said plungers.

1. Liquid distribution apparatus comprising manifold means, saidmanifold means having first inlet means for connection with a liquid tobe distributed, said manifold means having a plurality of spaced outletholes formed therein and in communication with said first inlet meansfor distributing liquid, said manifold means having second inlet meansfor connection to a cleaning solution, and plunger means movably mountedwith respect to said manifold means for movement into and out of saidoutlet holes for closing the holes and forcing out any particles tendingto clog the holes, and means for automatically connecting said secondinlet means with said outlet holes when said plunger means moves intosaid outlet holes and closes said outlet holes.
 2. Apparatus as definedin claim 1 wherein said plunger means comprises a plurality of separateplungers each of which has a sliding fit with one of said outlet holes.3. Apparatus as defined in claim 1 wherein said means for automaticallyconnecting said second inlet means with outlet holes comprises valvemeans.
 4. Apparatus as defined in claim 1 wherein said manifold meanshas an elongated passage formed therein in communication with said firstinlet means, said outlet holes opening into said passage said passagebeing of decreasing cross-sectional dimension from said first inletmeans toward the opposite end of said passage.
 5. Apparatus as definedin claim 4 wherein said first inlet means is disposed adjacent themidportion of said manifold means and said elongated passage is ofdecreasing cross-sectional dimension in opposite directions from thecenter of said manifold means.
 6. Apparatus as defined in claim 4wherein said first inlet means is disposed adjacent one end of saidmanifold means, said elongated passage decreasing in cross-sectionaldimension toward the central portion of said manifold means. 7.Apparatus as defined in claim 1 wherein said plunger means comprises aplurality of separate plungers each of which has a sliding fit with oneof said outlet holes, and seal means disposed in surroundingrelationship to each of said plungers to provide a liquid-tight sealtherewith.
 8. Apparatus as defined in claim 7 including means forselectively reciprocating said plungers.
 9. Apparatus as defined inclaim 1 wherein said plunger means comprises a plurality of separateplungers each of which has a sliding fit with one of said outlet holes,the end portion of each of said plungers which is adapted to slidewithin one of said outlet holes being of reduced dimension as comparedto the remainder of the associated plunger.
 10. Liquid distributionapparatus comprising manifold means, said manifold means having firstinlet means for connection with a liquid to be distributed, saidmanifold means having a plurality of spaced outlet holes formed thereinand in communication with said first inlet means for distributingliquid, said manifold means having second inlet means for connection toa cleaning solution, plunger means movably mounted with respect to saidmanifold means for movement into and out of said outlet holes forclosing the holes and forcing out any particles tending to clog theholes, and valve means for selectively connecting said second inletmeans with said outlet holes, said plunger means comprising a pluralityof separate plungers each of which has a sliding fit with one of saidoutlet holes, said valve means being incorporated in at least one ofsaid plungers.